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Continental Car Lab | banana in the tailpipe

By Daniel Gardner, 03 Jul 2020 Car Advice

It seems unlikely that something as innocent as a banana could halt a car, so we found out

Banana in 1989 Holden Berlina tailpipe

Like so many depictions of cars in Hollywood, the big screen often paints a farfetched picture that straddles the line between automotive reality and automotive myth.

And a good example is the idea that you can disable a car by inserting a banana or two into its exhaust pipe.

The theory behind the trick would appear to make sense. If you prevent exhaust gasses from leaving the engine, fresh air and fuel will not be able to fill the cylinders and the entire Otto cycle ceases. But is that the reality in practice?

Beverly Hills Cop

Attempt 1

For our first attempt, two bananas were inserted into the tailpipe just as they were in the classic motion picture Beverly Hills Cop but, surprisingly, with a little struggle, the Berlina’s V6 engine started and ran.

With a dab of the accelerator, the brace of nanas was ejected, even though they had been loaded apparently with more force than in the movie.

Attempt 2

Undeterred, we then tried with a potato. Its more substantial composition allowed it to be forced into the exhaust system with a tighter fit and a better seal. Surely this would extinguish the Holden’s power.

Nope, it might have taken a little longer to start, but when revved, the pressure simply blew the jammed potato back out again with even more corresponding force than the pair of bananas.

Attempt 3

Perhaps more carefully fitted fruit would be the secret behind this story? Using a series of limes that were the same diameter of the tailpipe, a citrus bung may provide the blockage to kill our engine.

Once again, the exhaust aliens were simply fired out of the backbox like it was slamming tequilas.

Final attempt

For the last attempt to either prevent our Holden engine from running or simply cut out once started, the entire fruit salad was inserted and, for a good measure, taped in place. How could any discerning engine continue to run without any way of getting rid of its exhaust gasses?

Amazingly, not only did the trusty Lion still run, vegetable scientist Simon Telford even managed to drive it away. albeit with some very comical sound effects that were definitely not dubbed over in editing.

Berlina potato cannon

Perhaps what the scriptwriters were underestimating was the immense force and flow generated by the exiting gasses. Even at idle, a six-cylinder engine like the one commandeered for our experiment is producing nearly 2000 litres of gasses every minute and stopping that kind force requires some serious effort.

Read next: Exhaust pressure is enough to lift a 4x4

In the case of our first three attempts to recreate the movie myth, the sheer pressure of the gas inside the exhaust was easily enough to dislodge the fruit and veg, but in the final experiment, even when the obstruction was secured in place, the exhaust gasses were determined to find a way out through leaks in the system.

It certainly wouldn’t have been producing its full horsepower figure, but it was enough for our red classic to run and drive. Amazing.